A series of proposals has already been made for the design of plastic shell skis, in which consistently more or less costly forming steps were necessary for the individual components of the shell ski. For example, from AT-PS 309,282 it has already become known to assemble a plastic shell ski from an upper shell and a lower shell, and both shell parts exhibit webs projecting toward each other. Such webs were designed so that one web of one shell could be pressed in between two webs of the opposite shell and in this way could be inseparably joined to the opposite shell. Such a design requires that in the manufacture of the shell parts, a high degree of precision be maintained, and it must further be insured that the desired shape of the ski results. Moreover in these cases the assembly of such half shells is relatively costly. A shell design, once it is produced, can be reliably used only for one and the same type of ski with a certain length, and a later alteration of the height of the ski core is not easily possible, unless at the same time the danger of an inadequate connection of the two shell parts with one another is accepted.
According to the proposal in AT-PS 390,197 a shell ski was assembled from a number of sections, whose webs or legs perpendicular to the running surface, delimit hollow spaces, and according to this earlier proposal the bent sections are nested in one another, overlapping one another at least partially. The hollow spaces that are formed in this way between adjacent webs or legs can be subsequently filled with a filling material. In this design, as a result of the possible lateral shifting of the outer sections over the length of the ski relative to the inner section or sections, an easier matching to the desired outer contour of the ski seems possible. However, disadvantageous with such a design is the circumstance that because of the special design of the sections, at least in the lateral edge areas, a subsequent machining is not easily possible and furthermore, depending on the type of arrangement, the legs of the areas which are to be nested in one another have to be designed with dimensions reduced by the wall thickness of the section in the areas located between the legs, to produce an even outer contour. All these measures make any later precise machining difficult and thus here also for each ski norm the appropriate section must be prefabricated as precisely as possible.
Particularly with the use of fiber-reinforced plastics it is advantageous if sections that are as simple as possible are used and if the sections are produced in one simple production operation, for example by simple pressing, extrusion or pultrusion. Extrusion of fiber-reinforced sections is possible in principle, but can be used, however, only when there is a constant cross-section.